Inspired by this question. I was thinking about the constructed language I'm building and a group of countries in the history of my world, and ended up wanting to ask this question. Please do take the time to read all of the information under the main headers of "Info" and "A Little History Lesson" and think for a minute on the information contained in the subheaders. It will be important for answering the question and understanding the setting.

Info

Setting

I have a small little country, about the size of modern day Portugual, called Teyarzhaodaqua (From Teya-Řãonance-de-Aqua, lit, "The sun's domain of water") bordering (the longest border exactly parallel to) a country the size of modern-day China, called Aeðsta. Teyarzhaodaqua is not technologically or magically advanced, has very little education or status, and has few resources and weapons. Aeðsta is highly technologically advanced and has plentiful weapons and resources, lots of education, fine arts, sciences, and many people there are wealthy, as well as powerful mages.

Now, I have a scenario in which the language of Teyarzhaodaqua (From now on referred to as LC) becomes the official language (the only language spoken, surpassing the original language) of Aeðsta (from now on referred to as BC). That is to say, the language of LC completely replaces the native (and sole) language of BC (English).

Background on languages

The language of LC is hard to learn (at least for speakers of English, like BC), with an alphabet containing more than 75 characters (26 base letters plus 50 diacritics), difficult pronunciation, and confusing temporal reference system due to verb conjugations among ten sets of pronouns, and occasionally additional meaning is added to the written form by switching the color of the ink, which makes it a pain to write as well. It's not magical and doesn't have any kind of power/religious significance (as a matter of fact, it is occasionally viewed with scorn, since it has no religious significance), takes much more time and effort to learn, is a pain to work with, and isn't really connected to, say, important documents, scholarly findings, ancient works of literature, valuable information, etc. It's not economically important (not learned for trade) and not important for peace talks between the nations (LC'ers learned BC's language quickly, enabling communication.) So it's not important for diplomacy/money. It is a beautiful, melodic language at times, but the pronunciation of some words is alien, and occasionally harsh.

Important people, and all that stuff

The government of BC is a representative republic with three different law systems, each with an elected council: Law makers, law passers, and enforcers. There was no language barrier between the upper and lower classes of BC. LC is an oligarchy ruled by a group of spiritual leaders who make pass all laws within a small council.

A little history lesson

Isolation

The countries of LC and BC are nearly completely isolated from other civilizations due to being a landmass out in the middle of an ocean. LC was the original country that did not cover the entire landmass, but when BC came it conquered LC and all unused/unexplored land. BC was essentially one tribe that came over with one language. What makes this scenario interesting is that LC is literally cut off from time. All of the important technological developments of the rest of the world--from the invention of the wheel to the invention of gunpowder--took much longer to develop. LC's tech level is similar to that of Medieval Europe. BC, on the other hand, has 19th/20th century tech.

Barrier of Nature

Geographically, the little continent where BC and LC are is isolated by a formidable wall of defenses, namely a ring of jagged rocks made of graphite that has been compressed under heat, pressure, and time to create diamond "teeth" that form a vast barrier around the continent. Strong currents mean ships are pulled against the rocks with enough force to smash through wood. Past the diamonds, on seemingly dry land, there's a high wall of rock followed by a sudden depression. When tides are at their highest, the water on the other side of this wall surge over into the depressed ring--a death trap for survivors who paused to catch a breath. And if you make it past that? Say hello to poison elephants, trees that stab you, and carnivorous silkworms, as well as snakes whose venom turns flesh to stone and vampiric flowers.

Last bit of background

The local inhabitants, LC, having migrated from another plane of existence (the Light Plane, specifically a planet with 27 suns) have been eking out a living. And now, a couple thousand miles away, a fleet from BC approaches the continent . . . and survives.

The two communities are separated by a large mountain range that severs the land into a large chunk and a tiny chunk (that will later mark the boundaries between the countries.) BC is already at the medieval level, but LC is primitive.

The two countries develop, isolated from each other and the rest of the world, until they reach the level discussed earlier and BC looks up from all the stuff it's doing and wonders, hey, what is on the other side of those giant, treacherous mountains? And so we come to our scenario, where peace has been (grudgingly) made between the countries, (though conquest may still come) and they are exposed to each other's culture and language for the first time. The paths between the mountains are opened and . . . suddenly they are minutes away due to BC's communication technology.

Relationship Between BC and LC

BC's opinions of LC: "LC is inferior. It has less advanced technology, a weak government, a blasphemous sun-worshiping religion (can you believe they don't worship stone!?), a difficult language, strange customs, and to top it all off they're using up valuable resources and living on our land. But on the other hand, their language is connected to the language of the Light Plane, which is a potentially valuable resource, considering it might be useful for reading the magical tomes in our possession. Perhaps a temporary alliance would be useful. Our religion demands tolerance of other's beliefs, even if they are *sniff* blasphemous."

LC's views on BC: "BC is obviously inferior. They worship stone instead of the sun — how can that be forgiven? They speak a harsh, hard, primitive language while trying to make up for it with their "technology." Well, we'll show them how quickly we can adapt! And they can try all they want to take our land from us and change our religion — they'll regret it. But we need to try to be peaceful for now, since their technology and sciences might be useful to us."

Question (Hey, congrats on making it this far!)

What sociological event or trend (that have happened in our (real world's) history in similar situations) could have made BC make LC's language the lingua franca? It must adopt both the complex written form and the spoken form. It must become both the official language (what's taught) and the only spoken language (what's actually spoken in the street.) A number of "uneducated souls", like street urchins/criminals/poor people, won't speak much of it, but they have to know enough to get by. This doesn't have to happen immediately, but it has to happen over a period of about 50 years without any major upheavals in religion, government, etc.

18 Answers
18

When the Roman conquered Greece, they were so fascinated from their civilization that they put a straw in that land and started avidly sucking their culture.

It was common practice for students to go to Greece for studying in Greece. This didn't reach that far to replace Latin with Greek, but it gives you an hint of what could be a solution to your problem: not physical grandeur, but cultural.

Let the small country have such a strong cultural influence that the elites would find only natural to embrace its language and culture to legitimate themselves.

$\begingroup$Great answer. One thing to keep in mind is that the Romans were particularly adept at incorporating the better parts of their conquered enemies' culture into their own, and that they allowed conquered enemies to keep their culture and ways, so long as they didn't clash too hard with the Roman orders/govern/interests/etc$\endgroup$
– BlueriverSep 3 '18 at 20:57

8

$\begingroup$Obviously Latin survived as a language, but the most commonly used language for everyday purposes in the Roman empire was koine Greek, not Latin.$\endgroup$
– alephzeroSep 3 '18 at 22:22

Summary: LC are the primitives, the conquered; their language is complex but it becomes the language used. BC are the advanced, the conquerors, but their language is lost and LC becomes the language used.

There are many, many more of the LC people. The conquering BC people are from a geographically constrained accidental colony. They have advanced tech thanks to their provenance but only a few original colonists arrived and their numbers are few. Additionally they have trouble with inbreeding.

The LC people sprawl over an enormous area and number in the hundreds of millions. Resources and inbreeding are no problem.

The conquering BC people arrive and are lost in this sea of LC. It is no problem for a BC male to set himself up as a plantation owner, leveraging his tech to make a prosperous farm. This BC aristocrat can have multiple LC concubines who (as opposed to his main wife who is actually his first cousin) bear him many healthy children. In the first generation, his children grow up mostly speaking LC as they learn from their mothers. BC langauge is for speaking to their elders. In the second generation the BC-descended aristocrats are genetically majority LC. They speak LC to each other and BC only at weddings and funerals. Made wealthy by their time in LC country, these descendants also take charge in their ancestral BC homeland and bring the LC language back with them.

By the third generation LC is the main language in the developed areas of the BC homeland. People who speak BC as their first language are only found in communities left behind in the outlying BC countryside - isolated inbred rural people. These too are a dying breed as economically they cannot compete with plantations in the LC, and so come to the cities in BC and LC out of necessity and are assimilated.

$\begingroup$Which has actually happened, notably for the Norsemen/Normands in Normandy and their Varangian cousins in Russia... When the Normands conquered England they brought with them the French language.$\endgroup$
– AlexPSep 3 '18 at 19:24

$\begingroup$@AlexP - Thinking along those lines - I am sure BC loanwords would enter the LC language, especially for technological items that did not exist in LC land previously.$\endgroup$
– WillkSep 3 '18 at 19:28

$\begingroup$@AlexP While the Normans may have brought French with them, it hardly replaced the language used by the common man, making it a fairly poor example. The Scandinavians did change the language spoken by the British to a great deal, but they where the technologically superiors in a lot of ways (trade, ships, weapons -- pretty much anything besides buildings and arts) and they had the distinct advantage of Old English and Norse being very closely related.$\endgroup$
– ClearerSep 4 '18 at 11:45

1

$\begingroup$@Clearer: The example was what happened to the Norsemen when they settled in Normandy. The bit about the French was the icing on the cake: the conquered a land speaking a language related to their ancestral language, yet they brought into that land the language spoken by their French subjects. (And anyway, while English does indeed reflect a notable Scandinavian influence, it also has an absolutely massive French adstrate.)$\endgroup$
– AlexPSep 4 '18 at 12:24

It's a trend that goes viral: Initially LC is adopted by only a few of the most highly educated BC elite. It is chosen for this purpose precisely because of its difficulty and obscurity. Only the idle rich have the resources to learn it, and so it becomes the private language spoken by the most envied and admired people, who judge each other viciously on mastery of every nuance and grammatical idiosyncrasy. Overnight it becomes a viral trend among social climbers who aspire to be like the wealthy. However, it retains its cachet among the rich because of its difficulty. Only the truly wealthy can afford to study it with native speakers, and there's always another nuance to master.

Over the course of a couple of generations, LC filters down to all levels of society. The function it plays in society is that you can now tell someone's socioeconomic class after hearing them speak only a few words. In effect the society has now become linguistically stratified, and LC is what makes that possible.

The irony is that while there's nothing intrinsic about LC's culture or content that makes it appealing, the unexpected side effect is that native born teachers of LC now become very wealthy and influential, thus sending an unexpected infusion of money and power into the LC community.

$\begingroup$You save my time to write very similar answer ;-) The only thing that is not met from the original question is that the events should happen in a time frame of about 50 years. Yet I don't believe it is possible in so short time anyway so I wave off this OP's request.$\endgroup$
– IsterSep 4 '18 at 7:39

2

$\begingroup$One more twist in plot missed "It must become (...) the only spoken language (what's actually spoken in the street.)" - here I would say at some point someone in power, who already forgot why the language was adopted in the first place has to make a decision like "Why we keep hearing this obscure old, harsh BC language. Let's enforce the beautiful LC and forbid BC entirely". This way over some time it will really become dominant, even though many people will still use BC at home.$\endgroup$
– IsterSep 4 '18 at 7:45

$\begingroup$@Ister - 50 years IS about two generations, figuring about 20 years per generation.$\endgroup$
– Chris SunamiSep 4 '18 at 13:00

$\begingroup$This is a pretty good idea. (I gave it a +1 yesterday.) But I wanted to drop by and tell you that I rejected your edit on the main question, not because it wasn't a valid edit, but because I wanted to simply rephrase the "this question." And I felt that adding the question to the top would further motivate users to quietly skip over important information in their rush to be TFGITW. I hoped that users would read more of the critical text until they hit the main Q. Hope this didn't upset you.$\endgroup$
– FoxElementalSep 5 '18 at 23:16

We need to take a lesson from the modern-day United States, which is slowly adopting Spanish.

Whether or not the U.S. will completely adopt Spanish is not what I'm talking about. We're in the process. We're not printing government pamphlets in English and French or signs in English and German. We're slowly adopting Spanish.

In many areas (possibly most, I'm not that well travelled), you'll find (E.G.) signs in Home Depot stores that are English with Spanish small print.

As you get closer to the southern border, those signs change to Spanish with English small print (might not be common, but I've been in such stores).

Why is this happening?

Because the influx of the Hispanic culture has reached a critical-mass point where commercial interests, educational opportunities, and government services are impacted by the ability to reach people who don't speak English (well or at all). It is bolstered by a growing sentiment that all people should receive those benefits (commercial, educational, and governmental).

And the perspective is important. Even if the goal is to teach (for example) Hispanic children English, you still need to communicate with them. That means the teacher's job is easier if that person speaks Spanish. The shop owner may appreciate what little English they know, but he can better sell goods if he/she knows Spanish. Etc.

It should be noted that while I use Spanish and the Hispanic culture (as the largest of the ethnic sub-groups), we see this behavior everywhere where any ethnic group has become a substantial fraction of the whole. Walk through San Francisco's Chinatown and see how much English you can find. Walk through any of the Jewish or Amish communities and see how much English you can hear. Locally, this behavior is more common than we might think.

Conclusion

The social forces are:

The persistance of a tolerated sub-culture as it grows in relation to the dominant culture.

The increasing relevance of that sub-culture as a participant in government (whether it's reception of services or as a represented voting block. Your actual government structure will modify this.)

The increasing need by society to incorporate the youth of that sub-culture into its socio-economic structures. This is complicated, but it includes both buying power and store ownership, community leadership and community protection (think police, fire, medical, etc.), and the military. If 20% of your military volunteers are of a particular sub-culture and their contribution is valuable, speaking their language becomes critical.

The increasing desire to ensure meaningful citizenship of the sub-culture through education.

Finally, the willingness of the dominant culture to accomodate the sub-culture, to welcome them and make them equals.

The BC's have become soft by the wool of civilization. They have not known war for generations. Their generals sleep in silk sheets, their boys pick up the brush over the spear. Their army is a bureaucratic mess, little more than a daycare for perfumed nobles to offload their extra sons. Their officers buy their post with gold rather than the currency of blood and valour.

Unlike them, we have been fighting since time immemorial. The soil is poison, what little that is grown must be protected with iron and will. Every boy is taught the way of the sword, the land is hard and it's people must be harder.

A path has been opened up the mountain. The lands beyond are rich and fertile. The drums are beating, the warchiefs gather, they have elected a chief among them.

Us who have slept on hide and granite will have sons who will sleep on silk and satin.

By The Harp

The BC's tongue is harsh, there is no music in their language, no complexity for the emotion and depths of our epics. We Teyarzhaodaquan are rich in nothing but the music of our voice. We sell our songs to the nobles and poor alike.

Our troubadours travel the depths of the kingdom. On every fishing village, border post and manor we stop and share our songs.

The children copy our mannerisms, our sayings. The learned copy our tongue, our letters. The demand for our stories are such that books are written in our speech so that one may hear our story even where our troubadours cannot go.

It is not long before they abandon their own tongue, it has become the trend to memorize our songs, it becomes the cultured thing to do. People who cannot reference our songs become the rube and ignoramous. The rich compete to see who can speak our language the most fluently.

The old speech becomes the tongue of the vulgar. The vulgar, always wanting to become more than they are, abandon this too. In every corner of the country, a baby falls asleep to an Teyarzhaodaquan lullaby.

A larger dominant country is never going to replace their language with the language from a smaller inferior country.

However a larger dominant country might from a smaller superior country.

If you look at the world today, English is the language of science, the internet, computers and commerce so even in places like China and India with massive populations and their own native languages, English is pushed in the schools.

If the smaller country has superior education facilities, banking institutions, markets and trade routes, the larger country may send their young to be educated there. Suddenly the upper class in the larger country now have the ability to speak the language of the smaller country. They teach their children the language in preparation for their own education. The middle classes want to learn the language to give their children the chance to move up classes or at least work directly for the upper class. Eventually everyone is learning the language.

$\begingroup$English isn't really a good example in this case. English became the de facto world language because of (a) the global reach of the British Empire, (b) as the Empire was going into decline, the United States was becoming a force on the world stage, (c) the countries of the Anglosphere retained economic and military significance, and (d) the effects of the Second World War when English-speaking Allied troops were the most widely deployed around the planet.$\endgroup$
– Keith MorrisonSep 4 '18 at 15:32

$\begingroup$It's still the language of science and commerce which is why it is the defacto world language$\endgroup$
– ThorneSep 4 '18 at 23:19

Political Marriage is a common approach to brokering peace and absorbing other nations with BC, however generally speaking only one or two marriages are necessary.

For whatever reason, the leadership of LC has demanded that their dozens and dozens of unmarried elites be married as part of this.

The result is that across the upper strata of BC, most of the young nobility are now married to people who only natively speak LC's language.

The usual convention is that the newcomers learn the language and most likely their spouse learns their language in turn, but in general the language takes a back seat with the sheer scale of BC gently compelling conformity..

Not so now, those new husbands and wives from LC can talk to each other and there are so many of them the language remains strong amongst the upper echelons, their BC spouses scramble to learn the language.

Of course it's a far more elegant and beautiful language than BCs speech, so it soon becomes very trendy to be able to speak it, similar to the way french aristocracy marrying into the british royalty brought their language in the 1700s/1800s (note: my history is shaky on this one)

Soon enough any educated person is able to speak LC, and with the strong continuing presence of native speakers who teach bilingually to their own children, the language continues to filter down and becomes the defacto High-Class language of the nation. Anyone who is Anyone speaks it fluently, everyone else is inconsequential peasantry.

$\begingroup$At first this didn't appeal to me, but I see the elegance of the solution now. And it might make for more opportunities to expand the history of these countries in my writing, so +1!$\endgroup$
– FoxElementalSep 4 '18 at 13:06

$\begingroup$I was thinking something like this. My analogy was going to be roman emperor Constantine who was influential in the spread of Christianity. You only need one very influential person in power to bring about large scale change.$\endgroup$
– craqSep 5 '18 at 4:27

1

$\begingroup$I went with the idea of multiple arranged marriages because then it essentially instates an immediate high-class community who speak the language amongst themselves, thereby becoming realistically self-sustaining without being contrived or relying on chance as much.$\endgroup$
– RuadhanSep 5 '18 at 8:32

It turns out that LC's language, in spite of all it's complexities (or maybe because of it), is a perfect fit to be used as a formal language for BC's science and technology. While hard to learn, it makes interacting with BC's computer-like machines and interfaces a breeze. It helps BC's scientists to clearly and concisely describe complex problems and their solutions, something that, while possible, would be a lot harder to do in their native language. As such, LC's language becomes a mandatory part of any curriculum, not well liked at first but at least accepted for it's obvious usefulness.

Now the BC's version of the internet comes online, and becomes all the rage with the younger generations who all had 'LC' in school and are now using it as the defacto language of BC-net. This sets the stage for the process that slowly but surely replaces the original BC language with the 'new' LC language used by the 'BC-net generation' and their offspring.

For real life examples i'd look at the way English is becoming a second (nigh first) language for the 'internet generation' in European countries.

$\begingroup$+1 for the "it makes it easier to clearly explain problems and concepts" - if enough loanwords make it through that it becomes the "academic language", then it will also be adopted by anyone attempting to appear intellectual - especially if the language lends itself better to witticisms and wordplay. With the Upper Classes using the language, their Servants may have to learn the same, both causing it to filter down the to Lower Classes, but also generating a stigma against the original Language.$\endgroup$
– ChronocidalSep 4 '18 at 14:49

They may view the smaller country as inferior, they may or may not hate LC guts and everyone in it but one thing BC can't deny is that LC is loaded, it may be that they have gold mines everywhere or it may be that they are located at the center of the "silk road" of the area and a lot of commerce goes through it but whatever the reason is LC is really really rich.

The folks of BC might not like the folks of LC but they sure do love their money\gold, and the best way to make business with someone is to speak the same language as he does, over the years the people of BC started doing so much business with the people of LC that LC language has become the de facto standard language of BC.

$\begingroup$I see your point, but I explicitly stated "[LC and its language] [are] not economically important (not learned for trade) . . .it's not important for diplomacy/money." Upvote for content, but not an answer.$\endgroup$
– FoxElementalSep 3 '18 at 22:52

Administration

LC has always had a small population and few natural resources. The only reason they have survived so far is because they are ruthlessly efficient about everything they do.

Even during the conquest, despite superior strength and numbers, BC has learned just how efficient their logistics were. LC's militians, militians!!!, never went hungry, always had the appropriate gear, wounded were tended to and evacuated, and the units seemed to coordinate their movements effortlessly. The resistance may have been futile, ultimately, and their tactics were not so great, but the strategists of BC were left in awe of the logistics.

And once they finally got their grubby paws on LC's weak government, they discovered its administration.

They worship stone indeed, and commit everything to stone. A detailed history, in each town, reaching centuries back down to the founding! Indexed and organized in a way the best librarians of BC would never dream of, and at a scale they've never seen.

A well-defined set of responsibilities for each branch of the administration, with well oiled channels of communications so that not an ounce of gold or silver is unaccounted for, genealogy for centuries, possession of lands and noble privileges linked to the very act of law which enacted them, etc...

The king of BC is no fool, the generals see the potential immediately, and so they attempt to learn from the example... but it doesn't work. The very worthless culture of revering stone is what leads LC's people to only ever commit truth to stone, and to commit it in extensive details. Their very difficult language is due to the combination of precision and succinctness that those faithful records require.

Attempts to mirror this greatness fail, repeatedly. Attempts to commit the lyric and flowery language of BC to stone fails too: the stone cannot capture the necessary details, the fluidity of the letters, and worse the flowery language just takes too damn long.

So, resigned, the king has no choice but to take on the very administrators and scribes from LC, and let them use their own primitive language for the task; for it is as primitive as stone, and perfectly fits the medium.

Of course, letting the conquered record in their own language without supervision is unthinkable, and so the scribes of BC, promoted task masters, must now scramble to learn this primitive language they mocked. And the new scribes are taught this language too.

And soon, since it is so inefficient to translate back and forth, with all the imprecision this entails, between the written tablets and the oral language, administrators start using this language to talk to the scribes, and then to talk between themselves.

Would a noble trust their administrators blindly? Obviously not. Would a merchant trust the tax collector blindly? Obviously not. And so, little by little, the elite of BC learns the intricacies of LC.

Two generations later, the administration of BC is entirely conducted in the former language of LC; and it is well known that requests expressed using the common BC stall, due their imprecision, so communication with the administration is itself using the former language of LC.

$\begingroup$Wow! I . . . had no idea that my sweet LC was that smart! +1$\endgroup$
– FoxElementalSep 4 '18 at 13:10

1

$\begingroup$I think you might have mixed up the religion- LC worships light and BC worships stone. Or maybe I'm just reading this wrong? It seems like you're saying that because LC worships stone, they have an extensive stone library, etc.$\endgroup$
– John LockeSep 5 '18 at 22:14

It's never going to happen

The language in question has no significancy to anyone but the people who already speak it. There is simply no reason for any adult to learn the language, except as a curiosity or to speak to the primitive people with the hard to learn language. This should already make it abundantly clear that the language will never take over as the official language of another country.

Military conquest to spread the language

The BC nation is, in every way, superior to the LC nation when it comes to miltiary might. There's simply no way a mideval army of any size is going to defeat a modern army. The primitive army is severely hampered by logistics -- once it grows beyond a certain size, it cannot keep enough supplies around for the army to be effective. Adding the problems of disease and malnutrition in this kind of army, when it's effective, simply means that they'll never be able to defeat a modern army.

The modern army will simply retreat in their vehicles, while moving the primitives down with their flamethrowers, machineguns, grenades and poisonous gasses if they ever get into trouble. Or just by dropping loads of bombs on them from airplanes or shelling them with their massive artillery cannons from 20 kilometers away. No defenses the primitive army can create is going to a challenge for the modern army.

Even a single squadron of modern infantrymen will be able to defeat anything short of a full blown castle. Adding tanks, planes and artillery, means there's no chance that the primitive army will every make a dent in the modern army.

Completly destroying the primtive nations economy is going to be a piece of cake. Torch every field they find or drop land mines everywhere and the primitive nation is gone with no hope of recovery.

Spreading through culture is a dead end

It has been suggested that spreading the language through culture might work, but I (clearly) disagree. Spreading the language by writing songs and books may work for a short while, but it will never be able to take over a country where another language is already ingrained in every part of the country; such a country will have a very high degree of connectivity, meaning any change will have to work through a massive amount of inertia; you will have to change most things at once to make anything stick.

But there is hope!

It cannot happen in a short timeframe, but it may happen on a very long timeframe. Given that the LC people has no reason to adopt the BC language, the LC language will remain free from any major influence from the BC language. If the BC nation where to splinter into many fractions, some of the weaker ones near the LC nation, the LC language may gradually take over neighbouring regions. This could, very slowly, spread the language over centuries to the point where a unification of the BC fractions would make the LC language the major language of the BC state. This is a bit of a stretch though. Besides a few minor languages that where dominated by already major established languages, I cannot think of a single example where something similar has happened in real life.

$\begingroup$look at Russia before the Napoleonic wars$\endgroup$
– AndreySep 4 '18 at 14:05

$\begingroup$@Andrey The general population did not change their language; which is why the nobility panicked and hired tons of teachers to teach them Russian.$\endgroup$
– ClearerSep 5 '18 at 12:08

$\begingroup$you would be surprised how many words in Russian are French. This is remembering that Russian is Slavic, and french is Romantic, so they share almost 0 initially. So they were well on their way to becoming French. The reason they panicked was because French became the language of the enemy. Kind of how america lost German$\endgroup$
– AndreySep 5 '18 at 14:49

$\begingroup$Most of Europe have adopted some French, if not all. And yes, they panicked because the enemy spoke french, and the general population did not, making the Russian nobility closer to the enemy than the Russians.$\endgroup$
– ClearerSep 6 '18 at 15:22

When the first people from BC arrive, they survive the dangers you outline solely due to the assistance and knowledge of the LC peoples they encounter. Learning the language is a matter of necessity. Translating the terms necessary to ensure survival with enough precision to enable survival is cumbersome and time consuming, precisely because of the language traits you described. Therefore, anyone from BC who travel to LC need to have at least a basic level of fluency in the LC tongue.

Obviously, there is something worthwhile in LC, or the people of BC wouldn't bother after the initial trip. It could very well be the materials made available by those very dangers. If harvested, they could be put to great uses through the superior technology of BC. In the process of using and refining these materials, the terminology will spread throughout the BC language, and eventually everyone in BC will have at least some degree of understanding of the LC language.

Eventually, a superior fluency in LC's language becomes a sign of education and/or wealth, causing its use to become common among the elite, and eventually filtering down to the lower classes as well (since they need to be able to understand the upper classes when they interact).

In your question you have carefully excluded all potential reasons (number of speakers, technological and military advantage, cultural advantage, easiness, e.g., usability as a bazaar creole for traders, and even magic) for the big country to adopt the language of the small territory. It will not happen, just as the USA won't become a Navajo speaking country at any time.

Seems the governing factor for humans is that we learn our language(s) before the age of reason (whenever that might occur). And after that, acquiring another is hard, lengthy work.

So when you're positing a large nation adopting a new language as an "event", it's a highly unlikely event. Examples mentioned already - Chinatown, Amish, etc -demonstrate that if we can keep using our native language for daily life, we won't go to the trouble of learning another without a powerful incentive.

A Secret plot to conquer neighboring countries. The leaders of Aeðsta wish to conquer some neighboring countries without trouble and be able to occupy them for decates or longer. Thus they will learn the language of the vassal state Teyarzhaodaqua, promote some of them to high ranks in their military, feign being overwhelmed by a superior stratagem or magic, resulting in conquest of their own and the other nations. Then the true leaders of Aeðsta throw off the yoke of Teyarzhaodaqua and "liberate" the other countries, but insist on stationing troops there to keep the beguiling invaders of Teyarzhaodaqua from returning in a second wave of conquest. Sounds like the "Great Game" of Europe, no?

When the soldiers of BC's fleet set foot on LC's ground, so does the very first linguist BC has ever sent into LC. After observing the people for some time, he recognizes the prophesied sign of their own god in LC's language. Suddenly everyone wants to learn the complicated language as a sign of worship and enduring hardship for their god.

Clerics are the first to only speak and preach in the complicated language, so even the socially lower people learn by exposure. Teachers that speak LC's language are in high demand on the most prestigious universities and the rich and noble are the first to send their children to such schools in order to raise them in the light of god.

This trend trickles through to the lower social levels and in no more than 2 generations the old language of BC is only taught to those who have to understand the historical records.

You mentioned that BC had posesstion of some ancient texts that they thought LC might be able to translate.

The problem for BC is that LC doesn't want to make peace with the weak, rock-worshipping people on the other side of the mountain. Because the people in LC are small in number and have a complex language, it would be easy for them to keep their language from anyone in BC who wants to learn it. However, LC has been blessed by their light god(s) with a vision of a world in which all of BC worships the religion of the light. Because the religion in a country weakens as sciences and technology advance there, BC's motive is not religious, they think the texts can help them either advance their civilization or defeat LC. So BC and LC make a reluctant deal:

The deal

In order for BC to translate the text and know that LC isn't making up some random translation, at least one person from BC needs to be fluent in LC's language.

In order for LC to convert BC without conflict (which LC would never win), LC needs to teach BC about their religion and culture. What better way than with language? If people learn LC's language, they will also learn about LC religion. Once they see that light is clearly superior to rocks and convert, the good(s) of LC will bless them with good fortune and gifts.

BC makes learning LC's language mandatory. A native speaker from LC teaches someone from BC the language a little at a time, and using their modern communication, that person teaches everyone in BC at the same time. By the time BC deciphers the texts, most people are knowledgeable or even fluent in LC speak. Adoption of LC's religion soon follows, and the nations soon form a strong alliance based on mutual worship of the light. BC gives LC the luxury that their people have only dreamed of, and LC teaches BC how to worship the good(s) and make sacrifices. Now a need for something the other country has is turned into a mutual love of the light culture. Bonus: the text provides some valueable information that makes life even easier for BC and they can share all of the newfound wealth with LC.